JP2002271085A - Electromagnetic shield panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent electromagnetic shield panel used to block off electromagnetic waves coming from the outside into the inside of a building through openings and further electromagnetic waves leaking from the inside to the outside of the building through the openings, which electromagnetic shield panel blocks off electromagnetic waves over a wide frequency range between 0.1 MHz and 20 GHz and is applicable to large-area openings and excellent in durability. SOLUTION: A metal net body that implements electromagnetic shielding and a transparent conductive film are placed between two transparent plates, and a transparent plate, not less than 2 mm in thickness, is placed between the metal net body and the transparent conductive film to form the electromagnetic shield panel that implements electromagnetic shielding not less than -50 dB over a frequency range between 0.1 MHz and 20 GHz. The metal net body is of a 30 to 150 mesh and the sheet resistivity of the transparent conductive film is not more than 10 Ω/sq.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent electromagnetic shield used for shielding electromagnetic waves entering from the outside of a building to the inside through an opening and shielding electromagnetic waves leaking from the inside of the building to the outside through the opening. About the panel.

[0002]

2. Description of the Related Art In recent years, electronic devices such as OA and communication devices represented by personal computers have been widely used, and the era of advanced information has been advanced. These electronic devices often generate unnecessary electromagnetic waves, causing other electronic devices and electronic control devices to malfunction or become a noise source in many cases.

[0003] Unwanted electromagnetic waves generated by electronic devices penetrate from the outside of the building through the openings, causing the electronic devices and the like in the buildings to malfunction or become noise sources. Unnecessary electromagnetic waves from electronic devices leaking from the inside of the building to the outside of the building through the opening may cause electronic devices and the like outside the building to malfunction, become a noise source, and leak confidential information.

[0004] Therefore, providing electromagnetic shielding performance to the opening is an important requirement in the advanced information society.

In recent years, with the development and spread of communication equipment, the frequency of electromagnetic waves to be shielded is from 0.1 MHz to 20 GHz, from the frequency band of radio broadcast waves to the high frequency band called microwave used in televisions. Is required.

Japanese Patent Application Laid-Open Publication No. HEI 1-170098 discloses a technique for shielding electromagnetic waves of 10 MHz to 1 GHz, which is used for shielding electromagnetic waves of 400 MHz or less. A conductive grid formed by printing a conductive paste;
A method is disclosed in which a transparent conductive film for shielding electromagnetic waves of 0 MHz or more is separately provided on the surface of one transparent plate. Further, the conductive grid is formed by printing a conductive paste. The grid is made of silver paste with a line width of 1 mm.
Conductive wire with a thickness of 20 μm, diagonal length 10 cm
Square lattice, and the sheet resistance of the transparent conductive film is 10Ω.
/ □ is disclosed.

However, it is difficult to print a conductive paste in a grid pattern on the surface of a sheet glass used for a large-area opening, and a conductive grid or a transparent conductive film in which silver paste is baked is used for building. When used outdoors, it is difficult to maintain the electromagnetic shielding performance over a long period of time for the durability of the conductive grid or the transparent conductive film.

[0008]

Problems to be Solved by the Invention 0.1 MHz to 20 G
Provided is a highly durable electromagnetic shield panel that can be used for a large-area opening and shields electromagnetic waves in a broadband frequency band of Hz.

[0009]

An electromagnetic shielding panel according to the present invention is an electromagnetic shielding panel in which a conductor is provided between two transparent plates to perform electromagnetic shielding, wherein a metal mesh and a transparent conductive film are used as the conductor. An electromagnetic shielding panel characterized in that a transparent plate of 2 mm or more is provided between a metal mesh and a transparent conductive film, and electromagnetic shielding of -50 dB or more is performed in a frequency range of 0.1 MHz to 20 GHz.

[0010] In the above-mentioned electromagnetic shielding panel, the metal net is 30 to 150 mesh, and is integrated by using an intermediate film between transparent plates.

Further, in the above-mentioned electromagnetic shielding panel, the transparent conductive film has a sheet resistance of 10 Ω / □ or less.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Two transparent plates (a transparent plate a and a transparent plate b) are a plate glass such as a float plate glass, a heat ray absorption plate glass, a heat ray reflection plate glass, or a transparent glass plate such as a PVC resin, an acrylic resin, or a polycarbonate. It is a resin plate or the like.

A transparent plate a having a transparent conductive film formed on one surface is used. The transparent conductive film is a metal film such as gold, silver, rhodium, palladium, aluminum, an alloy of these metals, or a Nesa film or an ITO film. As these transparent conductive films, films formed by a method such as PVD or CVD can be used.

The transparent conductive film is disposed so as to face a transparent plate c disposed between the transparent plate a and the transparent plate b.

It is desirable that the sheet resistance of the transparent conductive film be 10 Ω / □ or less in order to obtain an electromagnetic shielding performance of −50 dB or more.

As the transparent plate c, a sheet glass or a transparent resin plate can be used similarly to the transparent plates a and b.

The metal net is disposed between the transparent plate b and the transparent plate c.

As the metal net, a net made of a metal wire such as stainless steel, copper, aluminum, and monel can be used. Alternatively, instead of the metal net, a net made of conductive fibers having a conductive film formed on the surface of polyester fibers may be used.

It is desirable that the metal wire to be used is formed with an anti-reflection blackened oxide film, an insulating coating such as silicone or neoprene. The anti-reflection coating can prevent the transparency of the opening from being impaired by reflection on the metal mesh.

The metal net is a diamond net, a square net, etc.
It is desirable that the mesh is a mesh of 50 mesh.

The transparent plate c is used to prevent the metal net and the transparent conductive film from interacting with each other to reduce the shielding effect in a specific frequency band. The thickness of the transparent plate c is desirably 2 mm or more. Considering that the electromagnetic shielding panel of the present invention is applied to the window frame, the thickness of the transparent plate c is 1
It is desirable to set it to 0 mm or less.

The transparent plate a, the transparent plate b, the metal net and the transparent plate c may be laminated and used. However, in consideration of rust prevention of the metal net and dew condensation on the transparent plate surface, polyvinyl butyral, ethylene It is desirable that they be integrated using an intermediate film such as vinyl acetate.

In the electromagnetic shielding panel of the present invention, a metal conductive tape (such as aluminum, copper, stainless steel, zinc or tin-plated copper tape) is attached to an edge portion of the electromagnetic shielding panel, and the conductive tape and a metal net are attached. It is preferable to improve the electromagnetic shielding performance by conducting the body and the transparent conductive film and grounding the conductive tape to a metal sash. For the conduction between the metal sash and the conductive tape, a conductive backup material or the like can be used.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

Embodiment 1 FIG. 1 shows a cross section of a main part of this embodiment.

Both the transparent plate a1 and the transparent plate b2 have a thickness of 3
mm plate glass, and a transparent conductive film 4
Was formed. As the transparent conductive film 4, a metal thin film of Ag and an insulating thin film of ZnO were alternately formed by a sputtering method, and the sheet resistance was 5Ω / □.

The metal net 5 is made of a stainless steel wire (having a wire diameter of 0.05 m) coated with a blackened oxide film for preventing reflection.
m) was plain-woven with 100 mesh.

A transparent plate glass having a thickness of 6 mm was used for the transparent plate c3.

The transparent plate a1, the transparent plate b2, the transparent plate c3 and the metal net 5 were integrated with the intermediate film 6 using polyvinyl butyral to form an electromagnetic shielding panel.

The electromagnetic shielding panel of this embodiment has a frequency of 0.1 MHz.
For electromagnetic waves in the frequency range of z to 20 GHz, -60
The shielding performance of more than dB was shown.

Example 2 Example 1 was repeated except that the thickness of the transparent plate c3 was 2 mm.
In the same manner as in the above, an electromagnetic shielding panel was produced.

The electromagnetic shielding panel of this embodiment has a frequency of 600 MHz.
Except for the shielding performance of −55 dB with respect to the electromagnetic wave having a frequency near z, the shielding performance similar to that of the first embodiment was shown with respect to the electromagnetic wave in the frequency range of 0.1 MHz to 20 GHz.

Comparative Example 1 FIG. 2 is a sectional view of a main part of Comparative Example 1. In Comparative Example 1, an electromagnetic shielding panel was produced in the same manner as in Example 1 except that the transparent plate c3 of Example 1 was not used.

The electromagnetic shielding panel of this comparative example has a frequency of 600 MHz.
The shielding performance against electromagnetic waves having a frequency of z was -38 dB.

The electromagnetic shielding performances of Example 1, Example 2 and Comparative Example 1 are as shown in FIGS. The electromagnetic shielding panel of Comparative Example 1 had a significantly reduced electromagnetic shielding performance with respect to an electromagnetic wave near 600 MHz.
In Examples 1 and 2 of the present invention, the electromagnetic shielding performance did not decrease as in Comparative Example 1.

As shown in FIG. 4, the thickness of the transparent plate inserted between the metal net and the transparent conductive film is set to 2 mm or more, so that the electromagnetic shielding performance against electromagnetic waves of other frequencies is -50 dB. It became clear that the above shielding performance could be obtained.

[0037]

The electromagnetic shielding panel according to the present invention has excellent durability and is -5 in a wide band of 0.1 MHz to 20 GHz.
It has high electromagnetic shielding performance of 0 dB or more.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an electromagnetic shielding panel according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of an electromagnetic shielding panel in Comparative Example 1.

FIG. 3 is a graph showing the performance of electromagnetic shielding of Examples 1 and 2 and Comparative Example 1.

FIG. 4 is a graph showing the relationship between the thickness of a transparent plate and electromagnetic shielding performance.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent board on which transparent conductive film was formed 2 Transparent board b 3 Transparent board c 4 Transparent conductive film 5 Metal net 6 Intermediate film

Claims (4)

[Claims] An electromagnetic shielding panel in which a conductor is provided between two transparent plates to perform electromagnetic shielding, wherein a metal mesh and a transparent conductive film are used as the conductor, and the metal mesh and the transparent conductive film are interposed between the metal mesh and the transparent conductive film. 2
An electromagnetic shielding panel provided with a transparent plate having a thickness of not less than 50 mm and having an electromagnetic shielding of not less than -50 dB in a frequency range of 0.1 MHz to 20 GHz. 2. The electromagnetic shielding panel according to claim 1, wherein the metal mesh has a mesh of 30 to 150 mesh. 3. The electromagnetic shielding panel according to claim 1, wherein the metal net is formed as a single body using an intermediate film between the transparent plates. 4. The electromagnetic shielding panel according to claim 1, wherein the sheet resistance of the transparent conductive film is 10 Ω / □ or less.